Cementitious coating containing non-abrasive filler

ABSTRACT

A PROTECTIVE COATING FOR CONCRETE, SLATE AND GRAVEL COVERED ROOF STRUCTURES PREPARED FROM A PREFFERED MIXTURE COMPRISING: WHITE CEMENT, WHITE WATERPROOF CEMENT, NONABRASIVE FILERS, A WHITENING AGENT, A SETTING AGENT, A BINDER, AND WATER.

L O-VI.

3,827,894 CEMENTITIOUS COATING CONTAINING NON-ABRASIVE FILLER Howard C.Hansen, 926 E. Hermosa Drive, Tempe, Ariz. 85281 No Drawing. Filed Dec.13, 1972, Ser. No. 314,863

Int. Cl. c041, 7/08 U.S. Cl 106-90 11 Clam]! ABSTRACT OF THE DISCLOSUREBACKGROUND OF THE INVENTION Field of the Invention This inventionrelates to coating products and more particularly to a coating productfor use on concrete, slate or gravel covered roof structures.

Description of the Prior Art Many roof coating products are availablefrom numerous suppliers and these prior art products are of variousformulations depending on regional climate conditions, cost of theingredients, type of roof structure and the like.

In relatively warm climates roof coatings are normally white in colorfor optimum reflectivity and thus minimum heat transfer. Prior art roofcoatings generally employ a portland cement of the usual gray color anddepend entirely on chemical whiteners to obtain the desired degree ofwhiteness.

Prior art roof coating of the above type are subject to relatively rapiddiscoloration due to the iron oxide content of the portland cement usedin their mixture, and thus a reduction in the reflectivity occurs as thediscoloration progresses.

Many of the prior art roof coatings generally employed are subject towater caused deterioration and will not withstand much in the way ofexternally applied forces. For example, a gravel roof is particularlysusceptible to these problems as may be evidenced by the loss of gravelresulting from a rain storm and by the gravel being kicked loose when aperson walks on the roof.

When roof coating products are commercially applied, they are usuallyapplied in at least two successive coats which are sprayed with suitableapparatus.

Many of the prior art products contain a sand fillerwhich causes rapiddestruction of the spraying equipment due to the abrasive nature of thesand.

The setting time between successive coats is of prime importance to acontractor due to the high cost of labor and the necessity of returningto a job site if this time is excessive. Thus, most of the availableproducts contain a chemical accelerator to speed up the set time.However,

3,827,894 Patented Aug. 6, 1974 "ice SUMMARY OF THE INVENTION Inaccordance with the present invention a new and useful roof coatingproduct is disclosed for use on concrete, slate, and gravel covered roofstructures.

The product of the instant invention includes a preferred mixture of twowhite cements which provide the product with strength, resistance towater caused deterioration, and have a naturalwhiteness; thus, thediscoloration which occurs in prior art mixtures does not occur in thismixture.

Some of the whiteness of the present product is derived from theinclusion of the white cements as hereinbefore described, and thiswhiteness is enhanced by the addition of a whitening agent.

A non-abrasive filler material is used in the present mixture to reducedamage to the applicating equipment.

The above elements are mixed into a homogeneous compound which isshipped to the job site in dry form. Preparation of this product for useincludes the addition of a binder, a chemical accelerator and water. Theamount of accelerator used is determined at the job site with humidityat that specific location and time being the determining factor.

Accordingly, it is an object of the present invention to provide a newand useful roof coating product for use on concrete, slate and gravelcovered roof structures.

Another object of the present invention is to provide a new and usefulroof coating product which is strong, resists water caused deteriorationand resists discoloration.

Another object of the present invention is to provide a new and usefulroof coating mixture which employs nonabrasive filler material toprolong the life of applicating equipment.

Still another object of the present invention is to provide a new anduseful roof coating product of the above described character the settingtime of which is controlled by adding a chemical accelerator thereto atthe time of use in quantity determined by the relative humidity at thatspecific time and location.

The foregoing and other objects of this invention, as well as theinvention itself, may be more fully understood from the followingdescription of the preferred embodiment.

DESCRIPTION OF THE PREFERRED "EMBODIMENT The roof coating product of thepresent invention is a mixture of various ingredients which providevarious desirable characteristics as will be described in detail, withone of these characteristics being a coating which is white in color andwill not discolor with age. The white color is particularly desirable inwarm climates due to its high reflectivity which provides a low heattransfer characteristic to the present product.

The desired white color of the product of the present invention and itsresistance to discoloration is derived from two ingredients. The firstingredient is the cement and the second is a whitening agent.

The cement is preferrably a mixture of two types of cement which arereferred to as white cements. As is well known in the art, white cementis a portland cement which does not contain any iron oxide and thus iswhite in color.

The first of these cements is white cement having what is commonlycalled high-early strength. High-early strength white cement dilfersfrom conventional cement in that it sets more rapidly.

The second of these cements is white cement containing well knownadditives which render it waterproof.

The mixture of the above described white cements not only provides anatural whiteness and waterproof characteristics to the present product,it also provides a rapidly achieved high resistance to externallyapplied forces. The resistance to externally applied forces will varyfrom manufacturer to manufacturer according to their particular formula.Thus, a cement having a high-early strength in the range of about 1,000p.s.i. is preferred.

The mix ratio of the above described white cements may be allowed tovary somewhat in accordance with the desired degree of resistance towater caused deterioration and the desired rapidity of of obtaining thehigh-early strength. If in a particular application obtaining highearlystrength is of prime importance, the amount of highearly white cementemployed should be increased with a proportionate decrease in the amountof white waterproof cement. If resistance to water caused deteriorationis important in a particular application, the above mentioned increaseand decrease in the quantities of the two cements should be reversed.The preferred mix ratio of the two cements is in the amount of about V2high-early white cement and about /2 white waterproof cement. It hasbeen determined that excessive deviations of the above preferred mixratio can cause undesirable results, i.e., if the product sets too fast,cracking may result, and if it sets too slowly, excessive time betweencoatings occurs.

A whitening agent is added to the above mixture of cements to augmentthe natural whiteness provided by the hereinbefore described whitecement and white waterproof cement. The preferred product employed asthe whitening agent is titanium which is a dark gray, lustrous, metallicelement in its natural state. As is well known, the basic elementtitanium may be processed into titanic oxide, sometimes known as titanicdioxide, TiO which is a white crystalline compound often used as apigment.

Also added to the above mixture of two cements is a non-abrasive fillersuch as talc. The non-abrasive characteristics of the filler isimportant so that damage to applicating equipment, such as sprayapparatus, may be held to a minimum.

It is noted that the mixture of the two cements, the whitening agent andthe non-abrasive fillers as thus far described, is a dry powderformulation. This formulation is thoroughly mixed into a homogenouscompound which is shipped from the manufacturing location to a job sitein this form.

At the job site a binder, a chemical accelerator, or setting agent andwater are added to the dry formulation in predetermined quantities andthorough mixing at this time is important to provide an easilyapplicable product of consistant quality and characteristics.

The binder employed may be any suitable well known binder such as epoxy,a silicate of soda solution and the like. However, the preferred binderis a polyvinyl acetate emulsion as is commonly used in roof coatings ofthis type.

The water added at the time of use should for obvious reasons he of tapor drinking water purity to prevent unfavorable reactions and/ordiscoloration.

The chemical accelerator, or setting agent, which may be employed tocontrol the setting time of the coating, will also determine thepot-life or working time of the product.

In the art, the term pot-life or working time refer to that period oftime between the formation of a wet mix and the solidification thereofinto an unworkable mass, that is, a mass which can no longer be appliedto a roof structure. The term setting time refers to that period of timebetween the application of a first coat and the application of a secondcoat.

The setting agent employed in the roof coating of the present inventionis calcium chloride, but it is not intended that this specific compoundbe construed as a limitation to the present invention as it should beunderstood that other well known setting agents could be employed, suchas magnesium chloride and the like.

As is well known, relative humidity is a prime factor which effects thesetting time in applications of coatings of this nature. Therefore, thecoating of the present invention ideally includes the addition of thesetting agent in various amounts as determined by the humidity readingat a specific job site.

By way of example, assume that a particular job site has a humidityreading of 20%, and that Vs part per weight of the setting agent addedto a specific quantity of the mix of the present invention will resultin a pot-life of 45 minutes and a setting time of between one and twohours. It should be noted that the setting time mentioned above willvary somewhat with the thickness of the coating, thus the above time ispredicated on a thickness resulting from an application of about two (2)gallons per 100 sq. ft. which is average for at least the firstapplication of a coating of this type.

Should it be desired that all the above parameters remain the same in aninstance where the humidity reading is 30%, parts by weight of thesetting agent would be needed to hold the pot-life and setting timesubstantially the same. Thus, it may be stated that with the aboveparameters, that about 3 part by weight is needed for each 10% ofrelative humidity.

It should be noted that the addition of the setting agent may be omittedfrom the present invention when the relative humidity at a particularlocale is low, that is, readings up to about 40%, without seriouselfects to the potlife and setting time. However, at readings from about40% and up the setting agent becomes very important.

The ingredients employed in the preparation of the product of thepresent invention are generally within the following proportions:

Ingredient: Parts by weight Whitener 2 to 3 Non-abrasive filler 8 to 11White cement 34 to 42 Setting agent M; to /a Binder 7 to 9 Water 75 toThe preferred mix and range of proportions is:

While the principles of the invention have now been made clear in anillustrated embodiment, there will be immediately obvious to thoseskilled in the art, many modifications of proportions, the elements,materials, and compounds used in the practice of the invention, andotherwise, which are particularly adapted for specific environments andoperation requirements without departing from those principles. Theappended claims are therefore intended to cover and embrace any suchmodifications within the limits only of the true spirit and scope of theinvention.

What I claim is:

1. A coating composition for use on concrete, slate and gravel coveredroof structures, said composition prepared from a mix comprising incombination: a whitening agent; non-abrasive fillers in the form oftalc; white cement; a binding agent; and water.

2. A coating composition as claimed in Claim 1 wherein said white cementincludes a mixture of high-early strength white cement and whitewaterproof cement.

3. A coating composition as claimed in Claim 1 wherein said white cementincludes a mixture of approximately /1 high-early strength white cementand approximately /2 white waterproof cement.

4. A coating composition as claimed in Claim 1 wherein said whiteningagent is titanium processed to form titanic oxide.

5. A coating composition as claimed in Claim 1 wherein said binderincludes a polyvinyl acetate emulsion.

6. A coating composition as claimed in Claim 1 further including asetting agent.

7. A coating composition as claimed in Claim 6 wherein said settingagent is added in quantities of approximately 5 part by weight for eachof relative humidity as determined by the relaive humidity reading atthe specific loctaion and time of use.

8. A coating composition as claimed in Claim 6 wherein said settingagent includes calcium chloride.

9. A coating composition for use on concrete, slate and gravel coveredroof structures, said composition prepared from a mix comprising incombination:

(a) a whitening agent in an amount of about 2 parts by weight to 3 partsby weight;

(b) non-abrasive fillers in the form of tale in an amount of about 8parts by weight to about 11 parts by weight;

(c) white cement in the amount of about 34 parts by weight to about 42parts by weight;

(d) a binding agent in the amount of about 7 parts by weight to 9 partsby weight; and

(e) water in the amount of about 75 parts by weight to about 85 parts byweight.

10. A coating composition as claimed in Claim 9 wherein said whitecement includes:

(a) a high-early strength white cement in the amount of about 17 partsby weight to about 21 parts by weight; and

(b) a white waterproof cement in an amount of about 17 parts by weightto about 21 parts by weight.

11. A coating composition as claimed in Claim 9 further including asetting agent in the amount of about M parts by weight to about /a partsby weight, the specific amount of said setting agent being approximatelypart by weight for each 10% of relative humidity taken at the specifictime and location of use.

References Cited UNITED STATES PATENTS 2,092,838 9/1937 Gardner 106972,929,729 3/ 1960 Waggoner 10689 3,102,039 8/1963 Manecke 106--973,240,736 3/1966 Beckwith 106--97 3,666,509 5/1972 Horwitz 106973,795,721 3/ 1974 Gilbert et a1. 106 89 2,991,186 7/1961 Furlan 106-98DELBERT E. GANTZ, Primary Examiner I. W. HELLWEGE, Assistant ExaminerUS. Cl. X.R. 106-97

